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1980 w116 300SD California model rear gear

Started by jtwoods4, 08 September 2022, 01:13 PM



I recently picked up a mint condition 1980 w116 300SD California model. I am trying to figure out what rear differential gear came in the California model because I can do 80mpg at 2400rpm. Yes 2400! I know my federal 49 state version 1980 300SD is closer to 3600 rpm at 80mph. So what's going on here? What was the special rear gear ration on the California 1980 model? I mean I can literally do 100mph at 3400rpm. I have never experienced this on a diesel before. It seems to be a one year only rear end for the California model 1980 300SD.

Thank you
1980 300SD


Maybe a diff swap during the car's lifetime?
1977 450 SEL 6.9 - Astralsilber


There was no special rear axle ratio for California 300SD models.  Both federal and California models were all 3.07:1.  Either someone has swapped out the rear axle as Daniel suggested, or the tach or speedometer are off because they're from a different car, and will not read correctly. 
1966 250se coupe`,black/dark green leather
1970 600 midnight blue/parchment leather
1971 300sel 6.3,papyrus white/dark red leather
1975 450se, pine green metallic/green leather
1973 300sel 4.5,silver blue metallic/blue leather
1979 450sel 516 red/bamboo


I would love to know what rear axle they swapped in! My only complaint about the SD is she's noisy on the highway! And getting some better MPG would be great as well.
1979 300 SD "Liesel", 282k Miles



Wow, that's a big delta. That rear end would have a ratio in the low 2.x range. I would imagine your acceleration is, shall we say, rather uninspiring?